1. Field
An exemplary embodiment relates to a display device, and more particularly, to an organic light emitting device.
2. Description of the Related Art
An organic light emitting device is a self-emitting device including a light emitting layer between two electrodes.
The organic light emitting device may have a top emission structure and a bottom emission structure depending on an emission direction of light. The organic light emitting device may be classified into a passive matrix type organic light emitting device and an active matrix type organic light emitting device depending on a driving manner.
However, the organic light emitting device may be easily degraded by an inner factor such as a degradation of a cathode electrode due to oxygen, a degradation of a reaction between the light emitting layer and an interface, and an external factor such as moisture, oxygen, ultraviolet rays, and product conditions. In particular, since moisture and oxygen permeated from outside have fatal influence on life span of the organic light emitting device, a sealing process in the organic light emitting device is very important.
In case of the organic light emitting device using a flexible substrate such as stainless steel or plastic film which has been recently developed, a sealing process is not perfect. In case of using a stainless steel substrate, the organic light emitting device has a top emission structure in which visible light is emitted toward the substrate. Therefore, a protective layer used in a sealing process has to be transparent. Further, the protective layer has to have a very small wafer vapor permeation rate so as to prevent the degradation of the organic light emitting device due to moisture or oxygen permeated from outside. A seal member used in the sealing process has to be thin.
Accordingly, it is very necessary to find a way capable of perfectly protecting elements formed on the substrate of the organic light emitting device.